GM Service Manual Online
For 1990-2009 cars only

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Engine Oil Pressure Sensor Signal Circuit

1

P0520

P0520

--

Engine Oil Pressure Sensor Ground Circuit

--

P0520

--

--

1. Engine Oil Pressure Indicator Always On

Circuit/System Description

The engine oil pressure (EOP) switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the engine control module (ECM) or the powertrain control module (PCM) should detect a low signal voltage input. With the engine running, the pressure switch opens, and the ECM/PCM should detect a high signal voltage input. The ECM/PCM tests the state of the EOP circuit with the ignition switch turned ON, and the engine turned OFF. If the ECM/PCM detects a high voltage input on the EOP signal circuit, DTC P1189 will set.

Reference Information

Schematic Reference

    •  Instrument Cluster Schematics
    •  Engine Controls Schematics for the 2.0L engine.
    •  Engine Controls Schematics for the 2.2L engine.
    •  Engine Controls Schematics for the 2.4L engine.

Connector End View Reference

    •  Instrument Panel, Gages, and Console Connector End Views
    •  Powertrain Control Module Connector End Views for the 2.0L engine.
    •  Engine Control Module Connector End Views for the 2.2L engine.
    •  Engine Control Module Connector End Views for the 2.4L engine.

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.

  1. Ignition ON, verify the scan tool Engine Oil Pressure (EOP) Switch parameter is Low.
  2. If not Low, replace the instrument panel cluster (IPC).
  3. Ignition OFF, disconnect the EOP switch.
  4. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.
  5. If not OK, test the signal circuit of the EOP switch for a short to ground. If the circuit tests normal, replace the ECM.
    If OK, replace the EOP switch.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 2.0L
    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 2.2L engine
    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine
    •  Control Module References for the ECM/PCM and IPC replacement, setup, and programming